Flying valve and well production method

ABSTRACT

The invention relates to oil and gas production and can be used for lifting liquid from wells by gas energy. The inventive flying valve comprises a tubular body, a detachable element in the form of a body of rotation and stoppers limiting the penetration of said element into the body. The detachable element or the tubular body or both of them are made of an oil-resistant material. The inventive method consists in periodically dropping said flying valve under the liquid level in the well to a lower bumper sub and in subsequently lifting the flying valve together with a liquid column which is disposed thereabove. The body and the detachable element are dropped separately, i.e. the detachable element of the flying valve is dropped before the body or vice versa.

FIELD OF THE INVENTION

This invention relates to the oil and gas production industry and can beused for lifting liquids from wells using gas energy, in particular, forlifting water from wells or shafts using air drawn or injected from thesurface. In addition, the claimed method allows cutting wax from thepipes surface in case of lifting oil from wells.

BACKGROUND OF THE INVENTION

The known constructions of flying valves for plunger lift contain atubular body and a detachable element, as a rule, in the form of a steelball (inventor's certificates SU 63138, SU 171351, SU 596710, SU 791939,SU 802525, and U.S. Pat. No. 2,074,012, U.S. Pat. No. 3,090,316, U.S.Pat. No. 6,209,637). All above devices satisfactorily work insmall-diameter wells when diameter and hence the mass of the body anddetachable element of flying valves are relatively small. With theincrease of well diameters and the mass of steel balls the use of flyingvalves becomes seriously complicated or even impossible due to jump ofshock loads resulting in deformation of tubes in wells, damage ofequipment and even destruction of steel balls.

SUMMARY OF THE INVENTION

The claimed invention allows to remove the above mentioned drawbacks anduse flying valves for lifting liquids from wells of any diameter.

According to the invention the flying valve contains a tubular body,entering it completely or partially a detachable element in the form ofa figure of revolution with a device restricting its entering the body,with the detachable element or tubular body being made fromoil-resistant (in case of water-water-resistant) elastic material, inparticular, from rubber of various brands.

The detachable element can be of a spherical, teardrop-shaped orellipsoidal form and in addition can be equipped with three or more flatstabilizers evenly distributed in the periphery. The stabilizers buttsfacing the body can serve as devices restricting the detachable elemententering the body of the flying valve.

Stoppers can be made not on the detachable element but on the body ofthe flying valve, for instance as projections located on the inner wallof the body.

In the wall of the body in the part of its height mismatching stoppersdrain ports can be made, and/or the wall of the body at the same levelcan be made in the form of silphon.

In addition, on the outer surface of the body at the level mismatchingthe drain ports annular grooves can be made complete with ring straps orwithout them.

In another embodiment on the outer surface of the body either strapswith longitudinal, inclined or spiral grooves throughout perimeter canbe installed or grooves can be made directly on the outer surface of thebody. On the inner surface of the body circular inserts can beinstalled.

On the outer rims of the detachable element's stabilizers rotatingcontacts can be installed. In another embodiment, planes of stabilizerscan be inclined with regard to the axis of the detachable element, andtheir outer rims are equipped with scrapers.

Elastic material of the detachable element may have inclusions and/orpatches of a more compact material which allows regulation of its weight(average density) keeping the same dimensions.

The well production method with use of a flying valve according toinvention includes periodical running of the flying valve under theliquid level in the well till the lower shock absorber and thesubsequent its lifting together with the column of liquid above theflying valve.

The runnings of the body of the flying valve and of the detachableelement of the valve are carried out separately, the detachable elementof the flying valve can be run first and then its body, or vice versa.

In the first case during the lifting the following proportion should beobserved:P _(se) /S _(ds) <P _(b) /S _(sab)Where P_(se)—weight of detachable element, S_(ds)—area of diametralsection of detachable element, P_(b)—weight of body, S_(sab)—sectionalarea of the flying valve body.

In the second case the sign between the right and left sides of equationis changed for the opposite:P _(se) /S _(ds) >P _(b) /S _(sab)

If the detachable element of the flying valve is equipped withstabilizers its lifting and lowering is carried out with stabilizersbeing positioned downward.

In a pulled-out position the body and the detachable element of theflying valve can be divided by the rod installed in the upper part ofthe well along its axis. The separation of the body and the detachableelement of the flying valve can be executed by short-time closing ofvalve on the pipeline exporting product from the well.

In case of insufficient gas pressure in the well or shaft, a decreasedpressure is maintained above the lifted liquid (continuously orperiodically).

The cycles of lifting and lowering of the flying valve can be monitoredby the change of temperature in the wellhead taking place withappearance in the wellhead of a next portion of lifted liquid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows one of designs of the flying valve with detachable elementin the form of a ball, according to the invention.

FIG. 2 shows the flying valve with drain ports in the tubular body, atthe outer surface of which there are annular grooves with ring straps inthem, according to the invention.

FIG. 3 shows the flying valve with the restricting device as aprojection on the inner wall of the body with the projection being madeof a material different from that of the body, according to theinvention.

FIG. 4 shows the flying valve with straps on the outer surface of thebody with longitudinal grooves throughout perimeter and with therestricting device being made as a projection on the inner wall of thebody, according to the invention.

FIG. 5 shows the flying valve with the valve body made as a silphon,according to the invention.

FIG. 6 shows two possible variants of the tubular body and detachableelement positional relationship, according to the invention.

FIG. 7 shows the flying valve with the detachable element complete withfour stabilizers, according to the invention.

FIG. 8 shows the flying valve with the detachable element complete withthree stabilizers and ballast made of a more compact material, accordingto the invention.

FIG. 9 shows the detachable element with inclined stabilizers whoseouter rims are equipped with scrapers.

FIG. 10 schematically shows the lowering of the flying valve into awell, according to the invention.

FIG. 11 shows the lifting of a column of liquid from the well (or fromthe shaft) by means of the flying valve, according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference number 1 in the drawings corresponds to the tubular body ofthe flying valve; number 2—the detachable element in the form of afigure of revolution entering body 1; 3—device restricting detachableelement's 2 entering body 1, various embodiments of these units haveadditional lettering (2 a, 3 b etc.).

The detachable element of the flying valve can be of a spherical,teardrop-shaped or ellipsoidal form and in addition can be equipped withthree or more flat stabilizers 4 evenly distributed in the periphery.The stabilizers 4 butts facing the body 1 can serve as devices 3 brestricting the detachable element 2 entering the body 1 of the flyingvalve.

Stoppers 3 can be made not on the detachable element 2 but on the body 1of the flying valve, for instance as projections 3 a located on theinner wall of the body 1.

In any case, the contact of detachable element 2 with tubular body 1 ofthe flying valve takes place not throughout the entire perimeter (notthroughout the circumference line) but at its separate sections. Andbetween detachable element 2 and tubular body 1 there is always a smallclearance with a certain part of gas passing through it. This gasbubbles through liquid being in the body which prevents the separationof element 2 from body 1 during lifting of the flying valve in the eventof a change of the lifting speed.

In the wall of body 1 in the part of its height mismatching stoppers 3 adrain ports 5 (FIG. 1) can be made, or the wall of body 1 at the samelevel can be made in the form of silphon 6 (FIG. 5). In addition, on theouter surface of body 1 at the level mismatching drain ports 5 annulargrooves 7 can be made complete with ring straps 8 (FIG. 2) or withoutthem.

Drain ports 5 allow to equalize the pressure on the detachable elementand exclude draining of liquid into the clearance between body 1 and thetube during the lifting of the flying valve.

In another embodiment on the outer surface of body 1 straps 9 withlongitudinal grooves 10 throughout perimeter can be installed, and onthe inner surface of body 1 circular inserts 11 can be installed (FIG.11).

Ring straps 8 from the outside of body 1 or circular inserts 11 on itsinner surface enable regulating the tubing flow area in wells as well asthe flow area of the flying valve itself.

Longitudinal grooves 10 made on straps 9 enable stabilize the process ofthe flying valve lifting, diminishing the possibility of its radialrunout and beating on the tubing walls.

On the outer rims of stabilizers 4 of detachable element 2 rotatingcontacts 12 can be installed (FIG. 7) which contributes to reducingfriction of detachable element 2 on the pipes wall in the well. Inanother embodiment, stabilizers planes 4 a can be inclined with regardto the axis of detachable element 2, and their outer rims provided withscrapers 13 (FIG. 9). The incline of stabilizers planes 4 a imparts todetachable element 2 rotation about its axis and help keep the presetposition during the lowering (without tumbling). Scrapers 13 provideadditional technical result in oil wells operation. They can be used forremoving wax accumulations at inner walls of pipes in wells.

Elastic material of the detachable element may have inclusions; insertsor edging of a more compact material which allows regulation of itsweight (average density) keeping the same dimensions. The edging, inaddition to weight regulation, helps retain the shape of the detachableelement preventing the swelling of rubber under the well productionimpact.

The well production method with use of a flying valve includesperiodical running of the flying valve under the liquid level in thewell till the lower shock absorber 14 and the subsequent its liftingtogether with the column of liquid above the flying valve (FIGS. 10,11).

The runs of the body of the flying valve and of the detachable elementof the valve are carried out separately, the detachable element of theflying valve can be run first and then its body, or vice versa. A bodyin the form of silphon 6 provides additional shock-absorption of impactloads when parts of the flying valve contact with the lower shockabsorber or between themselves.

Under the gravity force the detachable element of the flying valve fallsfree in the well overcoming some resistance of gas and submersions inliquid in the lower part of the well. The falling or running is stoppedwhen the detachable element reaches a lower shock absorber 14 (FIG. 10).The body 1 of the flying valve falls after the detachable element 2 andalso stops at a level of the lower shock absorber 14 resting upon thestoppers 3 of entrance of the detachable element 2 into the body 1.Elastic material of the detachable element 2 prevents deformation anddamage of the lower shock absorber 14, well pipes and the detachableelement 2 itself.

If the detachable element 2 of the flying valve is provided withstabilizers, then it is preferable to trip a detachable element withstabilizers being positioned downward.

After joining the body and detachable element of the flying valve closethe most part of a pipe flow area and gas having no possibility tobubble through a liquid layer begins, at the expense of pressure, pushout the flying valve together with a liquid column located above itupward to the well head (FIG. 11).

When lifted, the body and the detachable element of the flying valve canbe separated (if the detachable element is below) with the help of a rod15 placed in the upper part of the well along its axis. In this case therod 15 freely passes through a hole of the tubular body 1, tests on thedetachable element 2, stops it and separate from the tubular body 1 thatcontinues its moving upward. After that the parts of the flying objectseparately fall into the well beginning a next cycle of liquid liftingfrom the well.

The body and the detachable element of the flying valve can be separatedby a brief closing of a valve 16 on a pipeline 17 that exports gas fromthe well. In this case gas pressure above and below the flying valve isquickly leveled and the flying valve parts again separately falls down.

When a well is operated with a flying valve with a detachable elementsbeing below, the following relationship preventing separation of theflying valve parts during their lifting with liquid column must bestand:Pse/Sds<Pb/Sbs

Where Pse is the weight of the detachable element, Sds is the area ofdiametral section of the detachable element, Pb is the weight of thebody and Sbs is the sectional area of the body of the flying valve.

When the detachable element is above and the tubular body is below, thecharacter between the right and left sides of the equation changes intoopposite:Pse/Sds>Pb/Sbs

To keep these relationships, under limited possibilities to changesectional areas, material and, accordingly, the weight of body anddetachable element of the flying valve are selected. In that, elasticmaterial of the detachable element may contain fillers, as well asinclusions, edgings or inserts 18 made of more dense material. Thetubular body can be of composite type (for example, the body itself ismade of rubber while stoppers are made of metal) (FIG. 3).

Cycles of lifting and lowering of the flying valve can be controlled bya change in well head temperature that takes place when a lifted columnof liquid reaches the well head.

1-25. (canceled)
 26. A flying valve comprising a tubular body,detachable element in the form of a body of rotation entering saidtubular body and stoppers limiting the penetration of said element intothe body with said flying valve being differed by the fact that thedetachable element and/or the tubular body are made of an oil-resistantelastic material.
 27. A flying valve as set forth in claim 26, whereinsaid detachable element has spherical, tear-shaped or ellipsoid form.28. A flying valve as set forth in claim 26, wherein said stoppers aremade in the form of shoulder seats located on internal surface of thebody.
 29. A flying valve as set forth in claim 28, wherein drain portsare made in the body wall and located on a part of its height at a levelnot coinciding with said stoppers.
 30. A flying valve as set forth inclaim 28, wherein said tubular body wall is made on a part of its heightat a level not coinciding with said stoppers as a silphon.
 31. A flyingvalve as set forth in claim 26, wherein annular grooves, in which ringstraps are placed in, are made on the external surface of said body at alevel not coinciding with said drain ports.
 32. A flying valve as setforth in claim 26, wherein straps with longitudinal grooves are placedon the external surface of said body.
 33. A flying valve as set forth inclaim 26, wherein circular inserts are placed on the internal surface ofsaid body.
 34. A detachable element of said flying valve is accomplishedas a body of rotation and is made of oil and lubricant-resistant elasticmaterial.
 35. A detachable element as set forth in claim 34, whereinsaid detachable element is provided at least with three flat stabilizersthe end faces of which face said body serve as said stoppers forentering said detachable element into the body of said flying valve andend faces of said stabilizers are provided with rotating contacts.
 36. Adetachable element as set forth in claim 34, wherein said detachableelement is provided at least with three flat stabilizers the end facesof which face said body serve as said stoppers for entering saiddetachable element into the body of said flying valve and plains of saidstabilizers are inclined to an axis of said detachable element.
 37. Adetachable element as set forth in claim 34, wherein said detachableelement is provided at least with three flat stabilizers the end facesof which face said body serve as said stoppers for entering saiddetachable element into the body of said flying valve and external edgesof said stabilizers are provided with scrappers.
 38. A method of welloperation with the help of said flying valve comprising a tubular body,a detachable element and devices restricting the entry of saiddetachable element into said body and comprising a periodical run ofsaid flying valve under a liquid level in a well up to a lower shockabsorber followed by its lifting together with a liquid column beingabove said flying object with said body of said flying valve and saiddetachable element running separately wherein said detachable elementand/or said body of said flying valve are made of elastic materialresistant to well products exposure.
 39. A method as set forth in claim38, wherein the run of said detachable element of said flying valve isfollowed by the run of its body with using said flying valve for which:Pse/Sds<Pb/Sbs where Pse is the weight of the detachable element, Sds isthe area of diametral section of the detachable element, Pb is theweight of the body and Sbs is the sectional area of the body of theflying valve.
 40. A method as set forth in claim 38 wherein the run ofsaid body of said flying valve is followed by the run of its detachableelement with using said flying valve for which:Pse/Sds>Pb/Sbs.
 41. A method as set forth in claim 39 wherein saiddetachable element of said flying valve is provided with three or fourflat stabilizers with said stabilizers being downward when tripping saiddetachable element.
 42. A method as set forth in claim 38 wherein saidbody and said detachable element of said flying valve are separated,when lifted, by closing a valve on a pipeline that exports gas from saidwell.
 43. A method as set forth in claim 38 wherein a decreased pressurein said well is maintained when liquid is lifted with the help of saidflying valve.
 44. A method as set forth in claim 38 wherein cycles ofsaid flying valve tripping are controlled by a change in wellheadtemperature.